This invention relates to safety guards for presses which have a reciprocating ram cooperating with a bed for fabricating a workpiece, and more particularly to such guards comprising a protective sheet which is moved in and out of a protective position in response to movements of the ram.
Guards for power presses, such as press brakes, are very well known. Existing guards include various means for moving a protective sheet or barrier away from the work area near the press bed as well as means for returning the protective sheet to its protective position prior to the commencement of a work cycle of the press.
A press brake is a press that is operated by the operator using both of his hands to position a workpiece or material on a work area or over a bed of the press. Unlike a punch press where a workpiece is positioned on a work area of the press and the operator then must usually press two buttons before a ram comes down swiftly to engage the workpiece, the press brake is a slower moving machine and both of the hands of the operator are generally required to control a rear portion of the workpiece in order to position a forward portion of the workpiece in the work area. A foot of the operator contacts a pedal which controls reciprocating movement of the ram. Therefore, the types of protective devices used during the work cycle on punch presses, such as control buttons and associated circuitry that requires that both hands of the operator be positioned on the buttons which actuate the press, are not feasible for press brakes.
Existing safety guards for press brakes include very complex mechanical devices, such as hydraulic systems that are interconnected with the foot pedal which the operator uses to control the operation of the press brake ram and thus initiate the work cycle of the press.
Until recently, many press brakes were operated without any protection for the hands of the operator. However, in recent years the enactment of legislation, such as the Occupational Safety and Health Act, directed to protection of the operator of such devices has given rise to a need for an economical, effective and efficient press brake safety guard.